...These elements can be used in building web applications and are reusable. Polymer can be particularly useful when building UI components. Instead of having to constantly rebuild components such as a specific navigation bar or button in different frameworks and for different projects, simply define this component once with Polymer, and you can use it again and again in your future projects.
Because Polymer is built on top of the web standards-based Web Components APIs, custom HTML elements made from it are built totally from the platform up and are interoperable across frameworks. ...